The present specification relates to wax blends comprising partial esters of polyols and montan wax acid and derivatives thereof, long-chain carboxylic acids and long-chain alcohols and to their use.
Mixtures of polar waxes, hydrocarbon waxes, soaps and paraffins are used as paste-forming waxes in petroleum-spirit solvents to produce shoe polishes. The solids content of these compositions is about 25-30% by weight; i.e., on application, from 70 to 75% by weight of the formulation passes into the environment in the form of the volatile solvent component. In order to reduce these emissions there is a need for aqueous formulations. With a view to consumer familiarity, these formulations ought not to bring any disadvantages in use and should be capable of being used, as hitherto, in the form of a paste in tins.
Water-based formulations include high proportions of emulsifiers, e.g., ethoxylated alcohols, short-chain alcohols or soaps, so that the wax components can be emulsified in the water. On application, this leads to soft films or films which are not resistant to water. Other recipes combine the waxes with polymer dispersions in order to enhance the hardness and water resistance of the film, but in this case a permanent film buildup is observed on the polished surface, which breaks over time and gives the surface a gray shade.
The object was therefore to provide wax blends which do not have the abovementioned disadvantages.
Surprisingly, a wax blend has now been found which may be processed without water-soluble emulsifier and permanent soaps to produce aqueous pastes and which can be applied in use to leather surfaces to give water-resistant, nontacky, elastic films without gray break. The drying times are shorter than with the known formulations, and the dried coat applied can easily be polished to highly glossy films.
The present invention therefore provides a wax blend comprising 10-80% by weight of an ester component A, 10-80% by weight of an acid component B, and 10-80% by weight of an alcohol component C.
As the ester component A, the wax blend of the invention comprises synthetic partial esters of polyhydric alcohols and long-chain carboxylic acids and/or derivatives thereof such as polyesters and urethanes thereof, and/or natural waxes having a correspondingly high OHN (hydroxyl number) such as, for example, carnauba wax; as acid component B it comprises long-chain wax acids such as montan wax acid or C32/36 guerbet acid; and as the alcohol component C it comprises long-chain alcohols having a chain length  greater than C18 such as Uniline alcohols from Petrolite.
Acid components for preparing the ester component A may be the following: montan wax acid, oxidates of long-chain olefins or paraffins and/or guerbet acid C32-36 in combination with long-chain fatty acids.
Alcohol components for preparing the ester component A may be the following: trimethylolpropane, pentaerythritol, dipentaerythritol, glycerol, diglycerol, sorbitol and sorbitan, N-alkylglucamines and dialkanolamines.
Individually, the ester component A consists of partial esters of polyols with carboxylic acids and carboxylic acid mixtures of chain length C16-36; partial esters of polyols with carboxylic acids and carboxylic acid mixtures of chain length C16-36, modified with polybasic carboxylic acids of chain length C4-36; partial esters of polyols with carboxylic acids and carboxylic acid mixtures of chain length C16-36, modified with aromatic or aliphatic diisocyanates; partial esters of polyols with carboxylic acids and carboxylic acid mixtures of chain length C16-36, modified with aromatic or aliphatic carboxylic acids of low molecular mass, or of any desired mixtures of the abovementioned substances; and also, if desired, additionally of natural waxes having an OHN greater than 20.
Preference is given to wax blends in which the number of OH groups in the alcohol component of the partial esters of the ester component A is  greater than =2, with the exception of 1,2-ethanediol and 1,3-butanediol. It is possible to use polyhydric primary alcohols, such as, for example, trimethylolpropane, pentaerythritol, their dimers or oligomers, and/or their ethoxylation products.
In the partial esters of the ester component A the degree of esterification is  less than 90%, preferably between 50 and 75%.
For modifying the partial esters of the ester component A with polybasic carboxylic acids it is usual to use tribasic and dibasic carboxylic acids, especially citric acid, tartaric acid, malic acid, itaconic acid, maleic acid, adipic acid, sebacic acid, dodecanedioic acid, dimeric fatty acid, phthalic acid and terephthalic acid. For modification with isocyanates it is common to use monofunctional and difunctional aromatic and/or aliphatic isocyanates.
In particular, for modifying the partial esters of the ester component A with short-chain carboxylic acids, it is usual to use saturated, unsaturated, hydroxy-functional fatty acids, aromatic carboxylic acids such as hydroxybenzoic acid, hydroxymethylbenzoic acid, and phenylacetic acid.
The acid component B consists mostly of montan wax acid, or of oxidates of long-chain olefins or paraffins, or of dimerization products of long-chain fatty compounds such as dimeric fatty acid or guerbet acid, or of mixtures of these abovementioned substances, or of mixtures of one or more of the abovementioned substances with one or more fatty acids.
The alcohol component C consists mostly of long-chain wax alcohols of chain length  greater than C30 or of guerbet alcohol of chain length  greater than C30 or of wool wax alcohol and other stearols, or of any desired mixtures of the abovementioned substances, or of mixtures of one or more of the abovementioned substances with one or more fatty alcohols.
The wax blend of the invention may be used in combination with other wax-like compounds, such as, for example, hydrocarbon waxes and/or natural waxes and/or polymer dispersions and known formulation auxiliaries for preparing aqueous pastes for leather care.
A W/O emulsion is prepared from this wax blend with the addition of small amounts of a compatibilizer and a base, preferably an amine. To improve the keeping properties, a preservative, e.g., Mergal K9, and a humidity regulator such as sorbitol or glycerol may be added.
To optimize the hardness of the paste and the film hardness it is possible to carry out blending with known formulation components.